No, the James Webb Space Telescope probably hasn’t detected signs of alien life, but it might soon

Were those “alien farts” that the James Webb Space Telescope (JWST) detected in the atmosphere of an Earth-like planet last year, or were they just methane clouds? A new study argues for the latter, potentially dampening hopes that life has already been discovered beyond our borders .solar system.

The controversial one exoplanet, named K2-18b, is a warm, watery world with a hydrogen-based atmosphere. It is located about 120 light-years from Earth and is in the habitable zone around its home star, where liquid water (and therefore possibly life) is possible.

The distant world made the news last year after observations with JWST‘s Near Infrared Spectrograph (NIRSpec) instrument revealed possible traces of a biologically produced gas called dimethyl sulfide (DMS) in the planet’s atmosphere. On Earth, this chemical is known only to come from microscopic marine animals such as phytoplankton – giving researchers hope that K2-18b’s oceans may also be swimming with life.

However, the detection came with caveats, mainly due to the weakness of the chemical signals when observed at such extreme distances from Earth.

“The DMS signal from the Webb telescope was not very strong and only showed up in certain ways when analyzing the data,” says lead author of the study Shang Min Tsaisaid a project scientist at the University of California, Riverside, in a rack. “We wanted to know if we could be sure.”

Related: What’s the best evidence we’ve found for alien life?

The new research, published Thursday (May 2) in The astrophysical diary letters, further slows down this tantalizing discovery. Motivated by the fact that organically produced DMS quickly dissipates in Earth’s atmosphere before it can accumulate in large quantities, the researchers used computer simulations to model whether DMS could ever reach detectable levels in the atmosphere of a hydrogen-rich exoplanet.

The team found that DMS can reach detectable levels – as long as the hypothetical bugs in K2-18b’s oceans pump out 20 times more DMS than plankton in the oceans. Soil.

That in itself is not a deal breaker for the potentially habitable water world; everything else we know about it makes the planet “an ideal situation to find life,” Tsai added.

However, the team’s research also found that it is highly unlikely that JWST would be able to separate a DMS signal from other, more common atmospheric gases at the specific wavelengths it examined with NIRSpec.

“The signal overlaps strongly with methaneand we believe that detecting DMS from methane is beyond the capabilities of this instrument,” Tsai said.

Simply put, there could be biological compounds in K2-18b’s atmosphere and fertile life in the oceans, but JWST probably didn’t discover it.

The good news is that JWST has another instrument on board – the Mid-Infrared Instrument (MIRI) – which is capable of detecting a wider range of wavelengths and may be much better suited to decomposing DMS from methane, the authors wrote of the research. Follow-up observations of K2-18b using MIRI are already planned for this year, and science results are expected before the end of the year. If there is life on K2-18b – farts or otherwise – we may soon have a much better idea.

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